1 //===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// \file 10 /// This file implements the BitVector class. 11 /// 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ADT_BITVECTOR_H 15 #define LLVM_ADT_BITVECTOR_H 16 17 #include "llvm/ADT/ArrayRef.h" 18 #include "llvm/ADT/DenseMapInfo.h" 19 #include "llvm/ADT/iterator_range.h" 20 #include "llvm/Support/MathExtras.h" 21 #include <algorithm> 22 #include <cassert> 23 #include <climits> 24 #include <cstdint> 25 #include <cstdlib> 26 #include <cstring> 27 #include <iterator> 28 #include <utility> 29 30 namespace llvm { 31 32 /// ForwardIterator for the bits that are set. 33 /// Iterators get invalidated when resize / reserve is called. 34 template <typename BitVectorT> class const_set_bits_iterator_impl { 35 const BitVectorT &Parent; 36 int Current = 0; 37 38 void advance() { 39 assert(Current != -1 && "Trying to advance past end."); 40 Current = Parent.find_next(Current); 41 } 42 43 public: 44 using iterator_category = std::forward_iterator_tag; 45 using difference_type = void; 46 using value_type = int; 47 using pointer = value_type*; 48 using reference = value_type&; 49 50 const_set_bits_iterator_impl(const BitVectorT &Parent, int Current) 51 : Parent(Parent), Current(Current) {} 52 explicit const_set_bits_iterator_impl(const BitVectorT &Parent) 53 : const_set_bits_iterator_impl(Parent, Parent.find_first()) {} 54 const_set_bits_iterator_impl(const const_set_bits_iterator_impl &) = default; 55 56 const_set_bits_iterator_impl operator++(int) { 57 auto Prev = *this; 58 advance(); 59 return Prev; 60 } 61 62 const_set_bits_iterator_impl &operator++() { 63 advance(); 64 return *this; 65 } 66 67 unsigned operator*() const { return Current; } 68 69 bool operator==(const const_set_bits_iterator_impl &Other) const { 70 assert(&Parent == &Other.Parent && 71 "Comparing iterators from different BitVectors"); 72 return Current == Other.Current; 73 } 74 75 bool operator!=(const const_set_bits_iterator_impl &Other) const { 76 assert(&Parent == &Other.Parent && 77 "Comparing iterators from different BitVectors"); 78 return Current != Other.Current; 79 } 80 }; 81 82 class BitVector { 83 typedef uintptr_t BitWord; 84 85 enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT }; 86 87 static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32, 88 "Unsupported word size"); 89 90 using Storage = SmallVector<BitWord>; 91 92 Storage Bits; // Actual bits. 93 unsigned Size = 0; // Size of bitvector in bits. 94 95 public: 96 using size_type = unsigned; 97 98 // Encapsulation of a single bit. 99 class reference { 100 101 BitWord *WordRef; 102 unsigned BitPos; 103 104 public: 105 reference(BitVector &b, unsigned Idx) { 106 WordRef = &b.Bits[Idx / BITWORD_SIZE]; 107 BitPos = Idx % BITWORD_SIZE; 108 } 109 110 reference() = delete; 111 reference(const reference&) = default; 112 113 reference &operator=(reference t) { 114 *this = bool(t); 115 return *this; 116 } 117 118 reference& operator=(bool t) { 119 if (t) 120 *WordRef |= BitWord(1) << BitPos; 121 else 122 *WordRef &= ~(BitWord(1) << BitPos); 123 return *this; 124 } 125 126 operator bool() const { 127 return ((*WordRef) & (BitWord(1) << BitPos)) != 0; 128 } 129 }; 130 131 typedef const_set_bits_iterator_impl<BitVector> const_set_bits_iterator; 132 typedef const_set_bits_iterator set_iterator; 133 134 const_set_bits_iterator set_bits_begin() const { 135 return const_set_bits_iterator(*this); 136 } 137 const_set_bits_iterator set_bits_end() const { 138 return const_set_bits_iterator(*this, -1); 139 } 140 iterator_range<const_set_bits_iterator> set_bits() const { 141 return make_range(set_bits_begin(), set_bits_end()); 142 } 143 144 /// BitVector default ctor - Creates an empty bitvector. 145 BitVector() = default; 146 147 /// BitVector ctor - Creates a bitvector of specified number of bits. All 148 /// bits are initialized to the specified value. 149 explicit BitVector(unsigned s, bool t = false) 150 : Bits(NumBitWords(s), 0 - (BitWord)t), Size(s) { 151 if (t) 152 clear_unused_bits(); 153 } 154 155 /// empty - Tests whether there are no bits in this bitvector. 156 bool empty() const { return Size == 0; } 157 158 /// size - Returns the number of bits in this bitvector. 159 size_type size() const { return Size; } 160 161 /// count - Returns the number of bits which are set. 162 size_type count() const { 163 unsigned NumBits = 0; 164 for (auto Bit : Bits) 165 NumBits += llvm::popcount(Bit); 166 return NumBits; 167 } 168 169 /// any - Returns true if any bit is set. 170 bool any() const { 171 return any_of(Bits, [](BitWord Bit) { return Bit != 0; }); 172 } 173 174 /// all - Returns true if all bits are set. 175 bool all() const { 176 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i) 177 if (Bits[i] != ~BitWord(0)) 178 return false; 179 180 // If bits remain check that they are ones. The unused bits are always zero. 181 if (unsigned Remainder = Size % BITWORD_SIZE) 182 return Bits[Size / BITWORD_SIZE] == (BitWord(1) << Remainder) - 1; 183 184 return true; 185 } 186 187 /// none - Returns true if none of the bits are set. 188 bool none() const { 189 return !any(); 190 } 191 192 /// find_first_in - Returns the index of the first set / unset bit, 193 /// depending on \p Set, in the range [Begin, End). 194 /// Returns -1 if all bits in the range are unset / set. 195 int find_first_in(unsigned Begin, unsigned End, bool Set = true) const { 196 assert(Begin <= End && End <= Size); 197 if (Begin == End) 198 return -1; 199 200 unsigned FirstWord = Begin / BITWORD_SIZE; 201 unsigned LastWord = (End - 1) / BITWORD_SIZE; 202 203 // Check subsequent words. 204 // The code below is based on search for the first _set_ bit. If 205 // we're searching for the first _unset_, we just take the 206 // complement of each word before we use it and apply 207 // the same method. 208 for (unsigned i = FirstWord; i <= LastWord; ++i) { 209 BitWord Copy = Bits[i]; 210 if (!Set) 211 Copy = ~Copy; 212 213 if (i == FirstWord) { 214 unsigned FirstBit = Begin % BITWORD_SIZE; 215 Copy &= maskTrailingZeros<BitWord>(FirstBit); 216 } 217 218 if (i == LastWord) { 219 unsigned LastBit = (End - 1) % BITWORD_SIZE; 220 Copy &= maskTrailingOnes<BitWord>(LastBit + 1); 221 } 222 if (Copy != 0) 223 return i * BITWORD_SIZE + llvm::countr_zero(Copy); 224 } 225 return -1; 226 } 227 228 /// find_last_in - Returns the index of the last set bit in the range 229 /// [Begin, End). Returns -1 if all bits in the range are unset. 230 int find_last_in(unsigned Begin, unsigned End) const { 231 assert(Begin <= End && End <= Size); 232 if (Begin == End) 233 return -1; 234 235 unsigned LastWord = (End - 1) / BITWORD_SIZE; 236 unsigned FirstWord = Begin / BITWORD_SIZE; 237 238 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) { 239 unsigned CurrentWord = i - 1; 240 241 BitWord Copy = Bits[CurrentWord]; 242 if (CurrentWord == LastWord) { 243 unsigned LastBit = (End - 1) % BITWORD_SIZE; 244 Copy &= maskTrailingOnes<BitWord>(LastBit + 1); 245 } 246 247 if (CurrentWord == FirstWord) { 248 unsigned FirstBit = Begin % BITWORD_SIZE; 249 Copy &= maskTrailingZeros<BitWord>(FirstBit); 250 } 251 252 if (Copy != 0) 253 return (CurrentWord + 1) * BITWORD_SIZE - llvm::countl_zero(Copy) - 1; 254 } 255 256 return -1; 257 } 258 259 /// find_first_unset_in - Returns the index of the first unset bit in the 260 /// range [Begin, End). Returns -1 if all bits in the range are set. 261 int find_first_unset_in(unsigned Begin, unsigned End) const { 262 return find_first_in(Begin, End, /* Set = */ false); 263 } 264 265 /// find_last_unset_in - Returns the index of the last unset bit in the 266 /// range [Begin, End). Returns -1 if all bits in the range are set. 267 int find_last_unset_in(unsigned Begin, unsigned End) const { 268 assert(Begin <= End && End <= Size); 269 if (Begin == End) 270 return -1; 271 272 unsigned LastWord = (End - 1) / BITWORD_SIZE; 273 unsigned FirstWord = Begin / BITWORD_SIZE; 274 275 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) { 276 unsigned CurrentWord = i - 1; 277 278 BitWord Copy = Bits[CurrentWord]; 279 if (CurrentWord == LastWord) { 280 unsigned LastBit = (End - 1) % BITWORD_SIZE; 281 Copy |= maskTrailingZeros<BitWord>(LastBit + 1); 282 } 283 284 if (CurrentWord == FirstWord) { 285 unsigned FirstBit = Begin % BITWORD_SIZE; 286 Copy |= maskTrailingOnes<BitWord>(FirstBit); 287 } 288 289 if (Copy != ~BitWord(0)) { 290 unsigned Result = 291 (CurrentWord + 1) * BITWORD_SIZE - llvm::countl_one(Copy) - 1; 292 return Result < Size ? Result : -1; 293 } 294 } 295 return -1; 296 } 297 298 /// find_first - Returns the index of the first set bit, -1 if none 299 /// of the bits are set. 300 int find_first() const { return find_first_in(0, Size); } 301 302 /// find_last - Returns the index of the last set bit, -1 if none of the bits 303 /// are set. 304 int find_last() const { return find_last_in(0, Size); } 305 306 /// find_next - Returns the index of the next set bit following the 307 /// "Prev" bit. Returns -1 if the next set bit is not found. 308 int find_next(unsigned Prev) const { return find_first_in(Prev + 1, Size); } 309 310 /// find_prev - Returns the index of the first set bit that precedes the 311 /// the bit at \p PriorTo. Returns -1 if all previous bits are unset. 312 int find_prev(unsigned PriorTo) const { return find_last_in(0, PriorTo); } 313 314 /// find_first_unset - Returns the index of the first unset bit, -1 if all 315 /// of the bits are set. 316 int find_first_unset() const { return find_first_unset_in(0, Size); } 317 318 /// find_next_unset - Returns the index of the next unset bit following the 319 /// "Prev" bit. Returns -1 if all remaining bits are set. 320 int find_next_unset(unsigned Prev) const { 321 return find_first_unset_in(Prev + 1, Size); 322 } 323 324 /// find_last_unset - Returns the index of the last unset bit, -1 if all of 325 /// the bits are set. 326 int find_last_unset() const { return find_last_unset_in(0, Size); } 327 328 /// find_prev_unset - Returns the index of the first unset bit that precedes 329 /// the bit at \p PriorTo. Returns -1 if all previous bits are set. 330 int find_prev_unset(unsigned PriorTo) { 331 return find_last_unset_in(0, PriorTo); 332 } 333 334 /// clear - Removes all bits from the bitvector. 335 void clear() { 336 Size = 0; 337 Bits.clear(); 338 } 339 340 /// resize - Grow or shrink the bitvector. 341 void resize(unsigned N, bool t = false) { 342 set_unused_bits(t); 343 Size = N; 344 Bits.resize(NumBitWords(N), 0 - BitWord(t)); 345 clear_unused_bits(); 346 } 347 348 void reserve(unsigned N) { Bits.reserve(NumBitWords(N)); } 349 350 // Set, reset, flip 351 BitVector &set() { 352 init_words(true); 353 clear_unused_bits(); 354 return *this; 355 } 356 357 BitVector &set(unsigned Idx) { 358 assert(Idx < Size && "access in bound"); 359 Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE); 360 return *this; 361 } 362 363 /// set - Efficiently set a range of bits in [I, E) 364 BitVector &set(unsigned I, unsigned E) { 365 assert(I <= E && "Attempted to set backwards range!"); 366 assert(E <= size() && "Attempted to set out-of-bounds range!"); 367 368 if (I == E) return *this; 369 370 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 371 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE); 372 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE); 373 BitWord Mask = EMask - IMask; 374 Bits[I / BITWORD_SIZE] |= Mask; 375 return *this; 376 } 377 378 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE); 379 Bits[I / BITWORD_SIZE] |= PrefixMask; 380 I = alignTo(I, BITWORD_SIZE); 381 382 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 383 Bits[I / BITWORD_SIZE] = ~BitWord(0); 384 385 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1; 386 if (I < E) 387 Bits[I / BITWORD_SIZE] |= PostfixMask; 388 389 return *this; 390 } 391 392 BitVector &reset() { 393 init_words(false); 394 return *this; 395 } 396 397 BitVector &reset(unsigned Idx) { 398 Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE)); 399 return *this; 400 } 401 402 /// reset - Efficiently reset a range of bits in [I, E) 403 BitVector &reset(unsigned I, unsigned E) { 404 assert(I <= E && "Attempted to reset backwards range!"); 405 assert(E <= size() && "Attempted to reset out-of-bounds range!"); 406 407 if (I == E) return *this; 408 409 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 410 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE); 411 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE); 412 BitWord Mask = EMask - IMask; 413 Bits[I / BITWORD_SIZE] &= ~Mask; 414 return *this; 415 } 416 417 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE); 418 Bits[I / BITWORD_SIZE] &= ~PrefixMask; 419 I = alignTo(I, BITWORD_SIZE); 420 421 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 422 Bits[I / BITWORD_SIZE] = BitWord(0); 423 424 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1; 425 if (I < E) 426 Bits[I / BITWORD_SIZE] &= ~PostfixMask; 427 428 return *this; 429 } 430 431 BitVector &flip() { 432 for (auto &Bit : Bits) 433 Bit = ~Bit; 434 clear_unused_bits(); 435 return *this; 436 } 437 438 BitVector &flip(unsigned Idx) { 439 Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE); 440 return *this; 441 } 442 443 // Indexing. 444 reference operator[](unsigned Idx) { 445 assert (Idx < Size && "Out-of-bounds Bit access."); 446 return reference(*this, Idx); 447 } 448 449 bool operator[](unsigned Idx) const { 450 assert (Idx < Size && "Out-of-bounds Bit access."); 451 BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE); 452 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0; 453 } 454 455 /// Return the last element in the vector. 456 bool back() const { 457 assert(!empty() && "Getting last element of empty vector."); 458 return (*this)[size() - 1]; 459 } 460 461 bool test(unsigned Idx) const { 462 return (*this)[Idx]; 463 } 464 465 // Push single bit to end of vector. 466 void push_back(bool Val) { 467 unsigned OldSize = Size; 468 unsigned NewSize = Size + 1; 469 470 // Resize, which will insert zeros. 471 // If we already fit then the unused bits will be already zero. 472 if (NewSize > getBitCapacity()) 473 resize(NewSize, false); 474 else 475 Size = NewSize; 476 477 // If true, set single bit. 478 if (Val) 479 set(OldSize); 480 } 481 482 /// Pop one bit from the end of the vector. 483 void pop_back() { 484 assert(!empty() && "Empty vector has no element to pop."); 485 resize(size() - 1); 486 } 487 488 /// Test if any common bits are set. 489 bool anyCommon(const BitVector &RHS) const { 490 unsigned ThisWords = Bits.size(); 491 unsigned RHSWords = RHS.Bits.size(); 492 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i) 493 if (Bits[i] & RHS.Bits[i]) 494 return true; 495 return false; 496 } 497 498 // Comparison operators. 499 bool operator==(const BitVector &RHS) const { 500 if (size() != RHS.size()) 501 return false; 502 unsigned NumWords = Bits.size(); 503 return std::equal(Bits.begin(), Bits.begin() + NumWords, RHS.Bits.begin()); 504 } 505 506 bool operator!=(const BitVector &RHS) const { return !(*this == RHS); } 507 508 /// Intersection, union, disjoint union. 509 BitVector &operator&=(const BitVector &RHS) { 510 unsigned ThisWords = Bits.size(); 511 unsigned RHSWords = RHS.Bits.size(); 512 unsigned i; 513 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 514 Bits[i] &= RHS.Bits[i]; 515 516 // Any bits that are just in this bitvector become zero, because they aren't 517 // in the RHS bit vector. Any words only in RHS are ignored because they 518 // are already zero in the LHS. 519 for (; i != ThisWords; ++i) 520 Bits[i] = 0; 521 522 return *this; 523 } 524 525 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS. 526 BitVector &reset(const BitVector &RHS) { 527 unsigned ThisWords = Bits.size(); 528 unsigned RHSWords = RHS.Bits.size(); 529 for (unsigned i = 0; i != std::min(ThisWords, RHSWords); ++i) 530 Bits[i] &= ~RHS.Bits[i]; 531 return *this; 532 } 533 534 /// test - Check if (This - RHS) is zero. 535 /// This is the same as reset(RHS) and any(). 536 bool test(const BitVector &RHS) const { 537 unsigned ThisWords = Bits.size(); 538 unsigned RHSWords = RHS.Bits.size(); 539 unsigned i; 540 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 541 if ((Bits[i] & ~RHS.Bits[i]) != 0) 542 return true; 543 544 for (; i != ThisWords ; ++i) 545 if (Bits[i] != 0) 546 return true; 547 548 return false; 549 } 550 551 template <class F, class... ArgTys> 552 static BitVector &apply(F &&f, BitVector &Out, BitVector const &Arg, 553 ArgTys const &...Args) { 554 assert(llvm::all_of( 555 std::initializer_list<unsigned>{Args.size()...}, 556 [&Arg](auto const &BV) { return Arg.size() == BV; }) && 557 "consistent sizes"); 558 Out.resize(Arg.size()); 559 for (size_type I = 0, E = Arg.Bits.size(); I != E; ++I) 560 Out.Bits[I] = f(Arg.Bits[I], Args.Bits[I]...); 561 Out.clear_unused_bits(); 562 return Out; 563 } 564 565 BitVector &operator|=(const BitVector &RHS) { 566 if (size() < RHS.size()) 567 resize(RHS.size()); 568 for (size_type I = 0, E = RHS.Bits.size(); I != E; ++I) 569 Bits[I] |= RHS.Bits[I]; 570 return *this; 571 } 572 573 BitVector &operator^=(const BitVector &RHS) { 574 if (size() < RHS.size()) 575 resize(RHS.size()); 576 for (size_type I = 0, E = RHS.Bits.size(); I != E; ++I) 577 Bits[I] ^= RHS.Bits[I]; 578 return *this; 579 } 580 581 BitVector &operator>>=(unsigned N) { 582 assert(N <= Size); 583 if (LLVM_UNLIKELY(empty() || N == 0)) 584 return *this; 585 586 unsigned NumWords = Bits.size(); 587 assert(NumWords >= 1); 588 589 wordShr(N / BITWORD_SIZE); 590 591 unsigned BitDistance = N % BITWORD_SIZE; 592 if (BitDistance == 0) 593 return *this; 594 595 // When the shift size is not a multiple of the word size, then we have 596 // a tricky situation where each word in succession needs to extract some 597 // of the bits from the next word and or them into this word while 598 // shifting this word to make room for the new bits. This has to be done 599 // for every word in the array. 600 601 // Since we're shifting each word right, some bits will fall off the end 602 // of each word to the right, and empty space will be created on the left. 603 // The final word in the array will lose bits permanently, so starting at 604 // the beginning, work forwards shifting each word to the right, and 605 // OR'ing in the bits from the end of the next word to the beginning of 606 // the current word. 607 608 // Example: 609 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right 610 // by 4 bits. 611 // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD 612 // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD 613 // Step 3: Word[1] >>= 4 ; 0x0EEFF001 614 // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001 615 // Step 5: Word[2] >>= 4 ; 0x02334455 616 // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 } 617 const BitWord Mask = maskTrailingOnes<BitWord>(BitDistance); 618 const unsigned LSH = BITWORD_SIZE - BitDistance; 619 620 for (unsigned I = 0; I < NumWords - 1; ++I) { 621 Bits[I] >>= BitDistance; 622 Bits[I] |= (Bits[I + 1] & Mask) << LSH; 623 } 624 625 Bits[NumWords - 1] >>= BitDistance; 626 627 return *this; 628 } 629 630 BitVector &operator<<=(unsigned N) { 631 assert(N <= Size); 632 if (LLVM_UNLIKELY(empty() || N == 0)) 633 return *this; 634 635 unsigned NumWords = Bits.size(); 636 assert(NumWords >= 1); 637 638 wordShl(N / BITWORD_SIZE); 639 640 unsigned BitDistance = N % BITWORD_SIZE; 641 if (BitDistance == 0) 642 return *this; 643 644 // When the shift size is not a multiple of the word size, then we have 645 // a tricky situation where each word in succession needs to extract some 646 // of the bits from the previous word and or them into this word while 647 // shifting this word to make room for the new bits. This has to be done 648 // for every word in the array. This is similar to the algorithm outlined 649 // in operator>>=, but backwards. 650 651 // Since we're shifting each word left, some bits will fall off the end 652 // of each word to the left, and empty space will be created on the right. 653 // The first word in the array will lose bits permanently, so starting at 654 // the end, work backwards shifting each word to the left, and OR'ing 655 // in the bits from the end of the next word to the beginning of the 656 // current word. 657 658 // Example: 659 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left 660 // by 4 bits. 661 // Step 1: Word[2] <<= 4 ; 0x23344550 662 // Step 2: Word[2] |= 0x0000000E ; 0x2334455E 663 // Step 3: Word[1] <<= 4 ; 0xEFF00110 664 // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A 665 // Step 5: Word[0] <<= 4 ; 0xABBCCDD0 666 // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E } 667 const BitWord Mask = maskLeadingOnes<BitWord>(BitDistance); 668 const unsigned RSH = BITWORD_SIZE - BitDistance; 669 670 for (int I = NumWords - 1; I > 0; --I) { 671 Bits[I] <<= BitDistance; 672 Bits[I] |= (Bits[I - 1] & Mask) >> RSH; 673 } 674 Bits[0] <<= BitDistance; 675 clear_unused_bits(); 676 677 return *this; 678 } 679 680 void swap(BitVector &RHS) { 681 std::swap(Bits, RHS.Bits); 682 std::swap(Size, RHS.Size); 683 } 684 685 void invalid() { 686 assert(!Size && Bits.empty()); 687 Size = (unsigned)-1; 688 } 689 bool isInvalid() const { return Size == (unsigned)-1; } 690 691 ArrayRef<BitWord> getData() const { return {&Bits[0], Bits.size()}; } 692 693 //===--------------------------------------------------------------------===// 694 // Portable bit mask operations. 695 //===--------------------------------------------------------------------===// 696 // 697 // These methods all operate on arrays of uint32_t, each holding 32 bits. The 698 // fixed word size makes it easier to work with literal bit vector constants 699 // in portable code. 700 // 701 // The LSB in each word is the lowest numbered bit. The size of a portable 702 // bit mask is always a whole multiple of 32 bits. If no bit mask size is 703 // given, the bit mask is assumed to cover the entire BitVector. 704 705 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize. 706 /// This computes "*this |= Mask". 707 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 708 applyMask<true, false>(Mask, MaskWords); 709 } 710 711 /// clearBitsInMask - Clear any bits in this vector that are set in Mask. 712 /// Don't resize. This computes "*this &= ~Mask". 713 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 714 applyMask<false, false>(Mask, MaskWords); 715 } 716 717 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask. 718 /// Don't resize. This computes "*this |= ~Mask". 719 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 720 applyMask<true, true>(Mask, MaskWords); 721 } 722 723 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask. 724 /// Don't resize. This computes "*this &= Mask". 725 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 726 applyMask<false, true>(Mask, MaskWords); 727 } 728 729 private: 730 /// Perform a logical left shift of \p Count words by moving everything 731 /// \p Count words to the right in memory. 732 /// 733 /// While confusing, words are stored from least significant at Bits[0] to 734 /// most significant at Bits[NumWords-1]. A logical shift left, however, 735 /// moves the current least significant bit to a higher logical index, and 736 /// fills the previous least significant bits with 0. Thus, we actually 737 /// need to move the bytes of the memory to the right, not to the left. 738 /// Example: 739 /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000] 740 /// represents a BitVector where 0xBBBBAAAA contain the least significant 741 /// bits. So if we want to shift the BitVector left by 2 words, we need 742 /// to turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a 743 /// memmove which moves right, not left. 744 void wordShl(uint32_t Count) { 745 if (Count == 0) 746 return; 747 748 uint32_t NumWords = Bits.size(); 749 750 // Since we always move Word-sized chunks of data with src and dest both 751 // aligned to a word-boundary, we don't need to worry about endianness 752 // here. 753 std::copy(Bits.begin(), Bits.begin() + NumWords - Count, 754 Bits.begin() + Count); 755 std::fill(Bits.begin(), Bits.begin() + Count, 0); 756 clear_unused_bits(); 757 } 758 759 /// Perform a logical right shift of \p Count words by moving those 760 /// words to the left in memory. See wordShl for more information. 761 /// 762 void wordShr(uint32_t Count) { 763 if (Count == 0) 764 return; 765 766 uint32_t NumWords = Bits.size(); 767 768 std::copy(Bits.begin() + Count, Bits.begin() + NumWords, Bits.begin()); 769 std::fill(Bits.begin() + NumWords - Count, Bits.begin() + NumWords, 0); 770 } 771 772 int next_unset_in_word(int WordIndex, BitWord Word) const { 773 unsigned Result = WordIndex * BITWORD_SIZE + llvm::countr_one(Word); 774 return Result < size() ? Result : -1; 775 } 776 777 unsigned NumBitWords(unsigned S) const { 778 return (S + BITWORD_SIZE-1) / BITWORD_SIZE; 779 } 780 781 // Set the unused bits in the high words. 782 void set_unused_bits(bool t = true) { 783 // Then set any stray high bits of the last used word. 784 if (unsigned ExtraBits = Size % BITWORD_SIZE) { 785 BitWord ExtraBitMask = ~BitWord(0) << ExtraBits; 786 if (t) 787 Bits.back() |= ExtraBitMask; 788 else 789 Bits.back() &= ~ExtraBitMask; 790 } 791 } 792 793 // Clear the unused bits in the high words. 794 void clear_unused_bits() { 795 set_unused_bits(false); 796 } 797 798 void init_words(bool t) { 799 std::fill(Bits.begin(), Bits.end(), 0 - (BitWord)t); 800 } 801 802 template<bool AddBits, bool InvertMask> 803 void applyMask(const uint32_t *Mask, unsigned MaskWords) { 804 static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size."); 805 MaskWords = std::min(MaskWords, (size() + 31) / 32); 806 const unsigned Scale = BITWORD_SIZE / 32; 807 unsigned i; 808 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) { 809 BitWord BW = Bits[i]; 810 // This inner loop should unroll completely when BITWORD_SIZE > 32. 811 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) { 812 uint32_t M = *Mask++; 813 if (InvertMask) M = ~M; 814 if (AddBits) BW |= BitWord(M) << b; 815 else BW &= ~(BitWord(M) << b); 816 } 817 Bits[i] = BW; 818 } 819 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) { 820 uint32_t M = *Mask++; 821 if (InvertMask) M = ~M; 822 if (AddBits) Bits[i] |= BitWord(M) << b; 823 else Bits[i] &= ~(BitWord(M) << b); 824 } 825 if (AddBits) 826 clear_unused_bits(); 827 } 828 829 public: 830 /// Return the size (in bytes) of the bit vector. 831 size_type getMemorySize() const { return Bits.size() * sizeof(BitWord); } 832 size_type getBitCapacity() const { return Bits.size() * BITWORD_SIZE; } 833 }; 834 835 inline BitVector::size_type capacity_in_bytes(const BitVector &X) { 836 return X.getMemorySize(); 837 } 838 839 template <> struct DenseMapInfo<BitVector> { 840 static inline BitVector getEmptyKey() { return {}; } 841 static inline BitVector getTombstoneKey() { 842 BitVector V; 843 V.invalid(); 844 return V; 845 } 846 static unsigned getHashValue(const BitVector &V) { 847 return DenseMapInfo<std::pair<BitVector::size_type, ArrayRef<uintptr_t>>>:: 848 getHashValue(std::make_pair(V.size(), V.getData())); 849 } 850 static bool isEqual(const BitVector &LHS, const BitVector &RHS) { 851 if (LHS.isInvalid() || RHS.isInvalid()) 852 return LHS.isInvalid() == RHS.isInvalid(); 853 return LHS == RHS; 854 } 855 }; 856 } // end namespace llvm 857 858 namespace std { 859 /// Implement std::swap in terms of BitVector swap. 860 inline void swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { LHS.swap(RHS); } 861 } // end namespace std 862 863 #endif // LLVM_ADT_BITVECTOR_H 864